The goals of my project are to further characterize, and therapeutically target, the alternative splicing of two transcripts that are aberrantly regulated in nervous system disease states. Tauopathies, which are a set of neurodegenerative diseases characterized by altered splicing of microtubule associated protein tau (MAPI), and glial cell tumors, which are associated with incorrect splicing of fibroblast growthfactor receptor 1 (FGFR1), are both incredible societal burdens in terms of neurological disease. The methods proposed in this application entail using a high-throughput screening assay to identify small molecule modulators of the splicing of these two nervous system pre-mRNA transcripts. Subsequent analysis of such compounds, such as digitoxin as a modulator of MAPT exon 10, will focus on transciptome-wide splicing effects. Bioinformatics analysis of splicing-sensitive microarraydata from drug-treated cells will provide a set of sequence motifs which are potential regulatory elements by which a drug is able to alter splicing. Investigation of such motifs will entail analysis of RNA binding proteins which are known to bind to the motifs, as well as characterization of previously unknown regulatory elements. Analyses will consist of the effects of small molecules on a candidate target protein's expression, post-translational modifications, and cellular localization. The application of high-throughput screening is not limited to identification of drugs that can alter important splicing events. By screening libraries of siRNA constructs, I intend to identify proteins that play a key regulatory role in MAPT and FGFR1 splicing. Data from such screens complements the small molecule data as key regulatory proteins are also likely drug target candidates. In total, this strategy for characterizing MAPT and FGFR1 splicing will not only further the understanding of basic alternative splicing regulation of the two transcripts, but will also make the first steps toward developing therapies aimed at the splicing abnormalities that contribute to neurodegeneration and malignant glial cell transformation. From a public health standpoint, this project proposes to further characterize two prolific nervous system disease processes, neurodegeneration and glial cell tumorigenesis, at the molecular level. This characterization and identification of drugs that can specifically target these molecular aberrations, such as in alternative splicing, are key steps in the transition to recognition of neurological diseases as individual and specific processes that require focused diagnosis and treatment.